<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        html,body{
            margin: 0;
        }
        header,footer{
            height: 100px;
            width: 100%;
        }
        header{
            position: fixed;
            top: 0;
            left: 0;
            right: 0;
            background-color: royalblue;
        }
        footer{
            position: fixed;
            bottom: 0;
            left: 0;
            right: 0;
            background-color: royalblue;  
        }
        #content #left{
            width: 300px;
            height: 100%;
            background-color: antiquewhite;

            position: fixed;
            left: 0;
            top: 100px;
            bottom: 100px;
        }
        #content #right{
            height: 1000px;
            margin-left: 300px;
            background-color: rosybrown;
        }
    </style>
</head>
<body>
    <!-- HTML页面铺满整个浏览器窗口，并且米有浏览器的滚动条，而且还可以跟随浏览器的大小的变化而变化 -->
     <!-- 自适应*定高
          （定宽+自适应）*自适应
          自适应*定高 -->
    <header></header>
    <div id="content">
        <div id="left"></div>
        <div id="right"></div>
    </div>
    <footer></footer>
</body>
</html>